Lens attachment.



G. H. DAY. I

LENS ATTACHMENT.

APPLICATION FILED JUNE 19 1912.

1, 1 1 9, 1 1, Patented D50. 8, 1914.

WITNESSES: INVENTOR j w; 0Rg H. DAY

B 1 v Y ATTORNEYS UNITE EL PATENT enrich,

GEORGE H. DAY, OF SOUTHBRIDGE, MASSACHUSETTS, I LSSIGNOR TO AMERICANOPTICAL COMPANY, OF SQUTHBBIDGE, MASSACHUSETTS, A CG'RPGRATZON OFMASSACHUSETTS.

To all whom it may concern Be. it known that I, .Groizsn citizen of the'United--'States, residing at Southbridge, 'in the county ofillorcesterand State of Massachusetts, have-invented -eertain new and usefulImprovements in Lens Attachments, of wnieh the tollcm'iiig is aspecification.

-. and lens screw for use i-n connectio'n there-- i with.

My invention relates toimprovenicnts in lens attachments, and has.particular reference to an improved fornroi lens attachment The leadingobject of my invention is the provision of improved meanswherehy the fVlens screwwill be locked against accidental loosening rotation.

. The further object of my invention is the provision in connection withlens screw locking mechanism ofan improved construction of lensattachment which will permit of relative yielding of thescrew lockingparts I to facilitate their-engagement in'tight interloc-king relation;

IOther obje'ctsend advantages'of my i'mproved lens attachment should bereadily I apparentjby reference to the following description takenin=e0n1iection-withthe aecoinpanying drawings, and it willbe-undenslightly. modified construction;

stood that-I may make any modifications in the specific details ofconstruction shown and described within the scope -of' the zippended-claims without departing from or exceeding the spiritof my'invention.

Figure I represents a plan view of a lens and ig. V I illustrates asimilar sectional view with the screw in tion.

In the drawings, in. which similar characters of reference are employedto denote corresponding parts throughout the several views, the numeral1 designates an ordinary lens having hearing against theedge thereof thestrap portion 2 of'the lens attachment,

its final locked posi- Speei flcation of Letters Patent.

" Application filed J'un'e 19, 1912. Serial No. 704,571.

H; DAY,

'. being shown in-flfull lines, while the Lens ATTACHMENT.

Patented 8., 1.914%.

said strapportion havingveiitending inward therefrom over thefaces ofthe *lens the upper lens clip can? beingprelier formed with a countersunt". recess 5 tom eeive the head 6 of the'iens screw; while lower ear has1"" n -"i therein the aperture 7 to recei th lower three. no. i? tion 8of the said lens-screw.

In ordinary construction of lens attachments much difficulty isexperienced'dne to loosening of the-lens screw and consequently of thelens 1 which is held clamped between the clip ears by saidscrews.Itistlie purpose of my invention to ei'ivintethis difiienlty, and tothis end I'i'i'orni the nn'i'ler side of the head 8 of {hell-11's -iththe ribs or tee h idnptedvf i terlocking engagement v 1' '10- fihich areformed on .e of t--.-.. countersunk portion-5 oft-he Up to sc'ertainpointthe lens clip and s ievf'may readil) be 're' htively rotated totion. Before the :ew is securely lockid with the ears tightly clamped.agains't lens, hon-ever, the 9 andlO tends to retard 'orspreventfurther tightening of the screw in those cases i'vhere f -I :ipply'mfv'invention toan ordinary lens" ch 'lhe'reason for this will'best beunder- 1 stoodby reference to Fig. V, irom which it.

eng'zigement or the {teeth i ee the screwinto post will be 'seen that asthe ribs 9 end 10 are riding past each other there is necessarily arelative'movement' of the screw headti and the adjacent lens clip ear 3,this movement tion of'the parts ordinarily when the teeth areinterlocked is indicated injFigL V in dotted lines and in Fig. V'I-ini'nll lines. It will be atonc'e apparent that this yielding of the ear3 cannot trike place after tl1e same is in normally tight en'gagementwith the lens 1. and that consequently further rotation ot the screw tosatisfactorily" tighten the same will. either exert such 'pressure ontlie ear 3 as to crush or crack the lens'orelse "1e teeth 9 and 10willbecoine burred or worn off. To'obvlate this difiiculty I haveresorted to certain expedients all of a similar general nature and allpro ducing the same general result althoughslightlv difi erin inappearance. In Fig. I, I have shownextending outward from thecountersink 5 and screw eperture 11 the slot 12, while in II, I. have11-0 and the lower lens clip ear 4, thenpper ear shown a slot 13extending inward from the employed as desired, or both may be used inconjunction with each other if preferred, the effect in any instancebeing that the portions of the clip ear 3 adjacent the countersink 5 andaperture 11 having a certain inherent degree of resiliency will yieldoutward slightly to relieve the lens of undue pressure while allowingthe teeth 9 and 10 to pass each other, the clip springing back intoplace as the teeth interlock to prevent reverse rotation of the screw.

' In Fig. III, I have attained this resiliency by cupping out the underside of the ear 3 adjacent the aperture 11, this'cupping out andconsequent thinning of the material allowing the central portion of theclip 3 to yield inward without bearing against the lens, while theresiliency of the cup ear will throw the yielding portion upward as soonas the pressure of the teeth against each other in turning is removed.

In Fig. IV, I have employed a still further modification inwhich I slotthe lower ear 4 by the slot 15, this permitting the tapped aperture 7 tospread slightly and allow the entire screw to yield upward somewhat asoccasion demands, the natural resiliency of the clip 4 causing the partsto spring together to satisfactorily engage the screw when the necessityfor the yielding thereof is passed.

From the foregoing description taken in connection with the accompanyingdrawings, the construction and operation of my improved lens attachingdevice should be readily apparent, and it will be seen that I haveprovided a simple, inexpensive and durable structure which on account ofthe resilient relative yielding movement of the screw and countersunkportion of the clip will permit of correct tightening of the lens screwwithout damage to the teeth and will cause the interlocking of the teethto absolutely prevent accidental reverserotation of the screw and whichwill thus entirely fulfil the objects of my invention.

I claim:

1. The combination with a lens, of clip ears in engagement therewith, alens screw passing through the lens and the clip ears, interlockingmembers carried by the lens screw and by one of the lens clips forsecuring the screw against accidental rotation, one of the aforesaidparts being slotted to permit of relative yielding of the interlockingmembers as the screw is rotated while forcing said members into tightinterlocking engagement upon cessation of rotation of the screw.

2. The combination with a lens, of a clip therefor having screwreceiving apertures formed therein, a lens screw passing trans verselyof the lens and clip, one side. of said clip having a portion thereofcut away to increase the resiliency thereof, and interlocking parts onthe screw and clip forced into locking-engagement with each other byformed therein and extending radially from I said aperture whereby saidear may yieldrelative to the securing means, and interlocking members onone of the clip ears and the holding means held in interlocking relationby the resiliency of the split clip ear.

I. A lens clip, including a pair of spaced clip ears having alinedapertures formed therethrough, one of the ears having a portion of theunder face thereof adjacent the aperture therein cut away to increasethe resiliency of that portion of the clip ear, one of the clip earshaving a slot formed therein and *extending outwardly from the apertureto increase the resiliency of the clip, a

. lens securing device passing through the ap ertures in the clip earsand having a head bearing against one of the clip ears, the said clipear and head having interlocking portions for holding the securingdevice against accidental rotation, the resiliency of the clipsoccasioned by slotting and cutting away portions thereof permittingrelative yielding of the interlocking parts as the lens securing deviceis' forced into position.

i In testimony whereof I ailix my signature in presence of twowitnesses.

GEORGE I-I. DAY.

Witnesses:

. ALICE M. Hoax,

IVIAURICE D. HERMAN.

